Recently, I purchased a Winnebago Motor Home powered by a 454 Chev engine coupled to a TH400 auto transmission. I purchased this motor home knowing it had a leaking rear main seal but thinking, as shade tree mechanics do, it would be a snap to repair. Low and behold to my surprise, I found the crankshaft had thrusted so badly the thrust bearing was worn almost completely away as well as the crankshaft thrust collar badly scarred. After many questions asked and many bulletins read, the only explanation I was able to acquire was ballooning of the torque convertor creating forward pressure on the crankshaft but, after sending the torque convertor to a remanufacturer capable of checking this out, they say its possible but not with this one, it looks brand new. Ideas from mechanics or anyone who may have experienced this type problem would be greatly appreciated. Need help! river rat